Process for obtaining olefins and/or carbon monoxide by absorption and desorption



United States Patent 3,305,596 PROCESS FOR OBTAINING OLEFINS AND/0R CARBUN MONQXIDE BY ABSORPTION AND DESURPTIQN Kurt Fischer, Neuotting (inn), and Josef Hirschbeck and Freimuth Lohiiier, Burgkirchen, Germany, assignors t0 Farbwerke Hoechst Aktieugesellschaft vormals Meister Lucius & Burning, Frankfurt am Main, Germany, a corporation of Germany No Drawing. Filed Mar. 16, 1964, Ser. No. 352,313 Claims priority, application Germany, Mar. 16, 1963, F 39,261 4 Claims. (Cl. 260-677) The present invention relates to a process for obtaining olefins and/ or carbon monoxide by absorption in ethanol amine-containing copper salt solutions and subsequent desorption at 3060 C.

German Patent 1,100,017 provides a process for separating olefins and/ or carbon monoxide from gaseous mixtures containing hydrocarbons, which have been freed in known manner from sulfur compounds, hydrocarbons having carbon-carbon triple bonds, and hydrocarbons that are liquid under normal conditions. In the first stage of the process the olefins and carbon monoxide are absorbed at 030 C. in a cuprous salt solution containing cupric salt. They are then desorbed at 3060 C. and the olefins and carbon monoxide are separated from each other by distillation.

It has now been found that it is very advantageous to heat the ethanol amine-copper salt solution used for absorbing the olefins and carbon monoxide to at most 60 C. in a heat exchanger and with the aid of a heating medium the temperature of which is above the temperature to be reached by the copper salt solution but still below 90 C.

It is advantageous to use hot water which is available in many cases from series-connected plants, for example installations for cooling pyrolysis gases, or water which has been heated to at most 90 C. by means of steam or other products.

When operating according to the process of the invention nowhere in the heat exchanger system the temperatures exceed 90 C. so that depositions of metallic copper from the copper salt solutions are avoided, which may 3,305,596 Patented Feb. 21, 1967 form at higher temperatures by reduction of copper ions to metal and oxidative decomposition of a corresponding amount of ethanol amine.

The process of the invention can be carried out with special advantage with the use of ethanol amine copper salt solutions containing, dissolved in water, ouprous nitrate, cupric nitrate and monoethanol amine and having a copper content of 150-200 grams per liter, 515% of the total amount of copper being present as bivalent copper.

When olefins and/or carbon monoxide are obtained with the use of ethanol amine-containing copper salt solutions by the process of the invention operation periods of up to one year are possible without difficulty, while with steam heated heat exchangers decomposition phenomena and copper depositions can be observed already after a few days.

We claim:

1. In the process for obtaining a member selected from the group consisting of olefins and carbon monoxide by absorption in ethanol amine-containing copper salt solutions with subsequent desorption at 30-60 C., the step which comprises heating the ethanol amine copper salt solution in a heat exchanger and with a heating medium the temperature of which is above the temperature to be reached by the coppersalt solution and below C.

2. The process of claim 1, which comprises using as heating medium a member selected from the group consisting of hot water from series-connected cooling systems, condensation water, and water heated to the required temperature.

3. The process of claim 1 wherein said desorption of said olefins and carbon monoxide is directly accomplished.

4. The process of claim 3 wherein said olefins and said carbon monoxide are separated from each other by distillation after said desorption.

References Cited by the Examiner UNITED STATES PATENTS 2,557,923 6/1951 Ray et a1. 260-677 2,894,049 7/1959 Ray et a1. 260-677 3,026,172 3/1962 Hirschbeck et al. 2606'Z7 ALPHONSO D. SULLIVAN, Primary Examiner. 

1. IN THE PROCESS FOR OBTAINING A MEMBER SELECTED FROM THE GROUP CONSISTING OF OLEFINS AND CARBON MONOXIDE BY ABSORPTION IN ETHANOL AMINE-CONTAINING COPPER SALT SOLUTIONS WITH A SUBSEQUENT DESORPTION AT 30-60*C., THE STEP WHICH COMPRISES HEATING THE ETHANOL AMINE COPPER SALT SOLUTION IN A HEAT EXCHANGER AND WITH A HEATING MEDIUM THE TEMPERATURE OF WHICH IS ABOVE THE TEMPERATURE TO BE REACHED BY THE COPPER SALT SOLUTION AND BELOW 90*C. 